Check if a string exists in the list
I have a bug with my list. Let me show you my idea: I have a loop, when loop 1 ends, the value will add to the List, and it will continue when the loop ends. Finally, I will be a List that includes all the values in each loop.
Then, I want to check if the value exists in the List. If there is, I'll do something.
Example:
Loop 1: List: A
Loop 2: List: A, B
Loop 3: List: A, B, A
Because the value A exists in the list. Then I will do something if A exists in List
List<string> list = new List<string>();
foreach (DataRow r in dt.Rows)
{
string Url = r["Url"].ToString();
list.Add(Url);
if (list.Contains(Url, StringComparer.OrdinalIgnoreCase))
{
//dosomething
}
}
But nothing happens. I wish you help me improve my code. Thank!!!
try it
if(list.Where(o=> string.Equals(Url, o, StringComparison.OrdinalIgnoreCase)).Any())
{
// Exists in the list
}
Or
if(list.FindIndex(o=> string.Equals(Url, o, StringComparison.OrdinalIgnoreCase))>-1){
// Exists in the list
}
Better approach would be to use List methods Exists
or Contains
, check out the following program:
List<string> l = new List<string>();
l.Add("Madrid");
l.Add("Barcelona");
l.Add("NewYork");
l.Add("Chicago");
if(l.Exists(x=>string.Equals(x,"Chicago",StringComparison.OrdinalIgnoreCase))){
Console.WriteLine("Done !!");
}
In the case of Exist, you can ignore the case using an enum StringComparison
, but that is not Contains
where you need to take care of this case, otherwise you need a custom IComparer
one to ignore the case